Panoramic image of oral cavity, i.e., oral pantomography, is one of significant methods for detecting oral diseases at present. It is advantageous to display images of all teeth on one X-ray film with small radiation doses.
At present, a digital panoramic image of oral cavity is usually formed by adopting a MI (Time Delay integration) sensor or a narrow area array sensor according to principles of TDI. IDE is based on several exposures of a same object. By using a delay integration method, TDI greatly increases a collection of light, thus improving a signal-noise ratio, and reducing a weight and a volume of a detector.
Working principles of TDI require a strict synchronization between a frame frequency of the detector and a movement rate of an object when scanning, and an corresponding relationship thereof is V=R*F, in which R is a pixel size (a constant), V is a relative movement rate between the object and the detector at the present moment, and F is the frame frequency of the detector at the present moment.
The problem is that, there may be situations that root imaging of incisor teeth of a patient may be unclear when the TDI sensor or the narrow area array sensor are used to form the panoramic image of oral cavity according to the principles of MI, if the patient has serious bucktooth, i.e., inclination angles of the incisor teeth are quite large, which may reduce definition of the panoramic image.